1. Field of Invention
The present invention relates to a machine tool and, more particularly, to a chain-type bit-storing apparatus for a machine tool.
2. Related Prior Art
A conventional chain-type bit-storing apparatus includes sprockets, a chain and a pivoting unit. The chain includes links. Each of the links includes a frame, a rotator, a pin and a socket. The rotator is rotationally connected to the frame. The pin is used to pivotally connect the frame to the rotator of another link. The socket, which is used for receiving a bit, is connected to the frame. The pivoting unit is used to pivot a selected one of the links, thus pivoting a selected one of the bits. The pivoting unit includes a guiding element and a pivoting element. The guiding element includes an arched track extending by and along an arched groove. The pivoting element includes an arched track extending by and along an arched groove. The arched track of the guiding element is movably placed in the arched groove of the pivoting element while the arched track of the pivoting element is movably placed in the arched groove of the guiding element. The pivoting element can be engaged with the selected link. Thus, the selected link is pivoted as the pivoting element is pivoted on the guiding element. However, the use of the conventional chain-type bit-storing apparatus is not without any problem. For example, it involves a complicated structure and therefore a high cost of manufacturing. Moreover, it requires high power to drive the pivoting element on the guiding element because of large friction between them and therefore involves a high cost of use and produces loud noise. In addition, the consumption of high power requires a large power system that renders an entire machine tool bulky.
Therefore, the present invention is intended to obviate or at least alleviate the problems encountered in prior art.